Each time I go into the BIOS it displays the CPU temp as 43 deg C, then after botting into windows xp MBM 5.2 tells me my CPU temp is 75 deg C!! How can the CPU shoots up 30 deg C so fast? Is MBM reporting the wrong data?

the only way to find out is start your computer all the way and run a large game for a few minutes then restart your computer and look in the bios

Well CPU temperature can increase very quickly, but not that quick (mine usualy gets to a pretty stable temperature after about 5 to 10 minutes), so i guess it could be reporting the wrong information (if you have another program that can get the information give it a try). Also 75C is quite hot, so if you find that, that is the actual temperature you may want to consider some new CPU cooling.

I think MBM is reporting the wrong data. Heating and Cooling by 30 deg C within 30 seconds? That's unbelievable.

I installed a hardware monitor for my system it read the cpu @ 47deg
I checked my bios and it said 43deg
I then used SANDRA and it said 43deg for my mobo and 37deg for my cpu and 50 deg for my power supply.

I'll believe the bios and I suggest you do the same.

One easy way to test is with the case open boot into bios. Next check the temp and fan rmp readings. Then stop the cpu fan, don't unplug it and don't use your finger (*Reason* horrible story involving 7000rpm fan and loss of a finger tip). If the temp goes up and the rpm goes down I'd say its doing its job.